US 1904079 A
Description (OCR text may contain errors)
April 18, 1933. Q L PQWELL 1,904,079
METHOD Am) APPARATUS FOR FORMING FOUNDATION COLUMNS Filed March 16. 1952 2 Shets-Sheeg l FIGJ. H62.
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BY W @I/[ r ATTORNEY5 April 18, 1933. C POWELL 1,904,079
METHOD AND APPARATUS FOR FORMING FOUNDATION COLUMNS Filed March 16. 1932 2 Sheets-Sheet 2 FIGS.
INVEN R- BY W M ATTORNEY;
Patented Apr. 18, 1933 UNITED STATES PAT NT OFFICE PANY, 01 NEW YORK, N. Y., A. CORPORATION OF DELAWARE METHOD ND APPARATUS non FORMING ronNnArIou COLUMNS This invention pertains to the making of foundations and the like for buildings and other structures, particularly foundations of the concrete pier or column type which are sunk into the ground by pneumatic caissons in order to reach suitable foo-tings j As will appear from the following description, the invention provides a number of ad vantages over pneumatlc cassion methods heretofore used. Y The working chamber at the lower end of the caisson is of larger diameter than the shaft that extends up to ground level. This means that the'only substantial frictional resistance encountered in sinking the caisson is that between the chamber and the wall of the excavation. The resistance is therefore held to a minimum, and is, furthermore, substantially constant, as distinguished from the usual practice, in which the caisson throughout its length is the full diameter of the hole whereby the frictional resistance increases with the depth of the excavation.
With theworking chamber of larger diameter than the shaft, liquid such as water or mud-laden fluid may be used to fill the annular space above the working chamber, thus serving not only to decrease the additional load required for sinking but also to prevent caving of the walls of the hole above the working chamber.
The frictional resistance of the caisson is practically constant at all depths; and the weight of the shaft is almost as great per foot of length as its displacement. Consequently, if the method of lowering the air pressure temporarily, to drop the caisson, is used, friction should prevent uplift and therefore only a small amount of additional weight, if any, will be required.
The present invention permits raising and recovery of the working chamber and shaft during the concreting operation, the raising usually being accomplished by air pressure or by using air pressure to assist hoisting cables or jacks.
Further and other objects and advantages will be apparent from the specification and claims, and from the accompanying draw- Application filed March 16, 1932. Serial No. 599,073.
ings which illustrate what isnow considered the preferred embodiment of the invention."
Fig. 'l-shows the apparatus during thesinking ofahole.
Fig. 2 shows the apparatus afterthe hole has been sunk to rock, or other footing, and
Fig. 3 shows the concreting operation under way after removal of the man-andmaterial lock, the caisson being partly raised.
Fig. 4 shows thec'ompletedcolumn or pier.
. Fig. 5 shows the concrete hopper on-the top of the shaft.-
Fig. 6 shows an enlarged view of themanand-material lock with the auxiliary shaftsealing partition in broken lines. f
Fig. 7 is an enlarged view of the sealing partition in operative position.
Fig. 8 is a viewon line88 of Fig. 7
Referring to the drawings, the working chamber 20 of the caisson'is provided with an upwardly extending man-and-material shaft 22. To begin operations the chamber is set in position on the ground surface'or on the bed of a stream or other body of water, or on the bottom of a hole which may have been dug by any known method.
In any event after the chamber has been set in position with suficient shafting to extend well above the starting surface, the hole is filled with liquid such as water or mud-laden fluid to balance the normal fluid pressure at the bottom ofthe working chamber and to prevent the walls of the hole from'caving above the working chamber. A man-andcHAnLns L. POWELL, on NEW YORK; N. Y., ASSIGNOR To CAISSON CONTRACTING com- :1,
material lock 24; isattached to the top of the shaft and air pressure is admitted to shaft and ejected from chamber 7 and shaft, men with digging. tools are lowered through the lock down the'shaft into the working chamber.
flooding chamber and shaft'with liquid to equalize the pressure in the working chamber. The weightsand platform, if used, and
lock are then removed, the required section of shaft added, the lock, and, if necessary, the platform and weights replaced, and air pressure applied to blow out the shaft and chamber' again. The men are then returned to work.
Another method of changing the shaft length, when frictional resistance exceeds buoyancy, is to place an auxiliary partition in the upper end of the shaft belowthemen as they come up theshaft. Suflicient air pressure is then maintainedbelow that partition to prevent flooding of shaft and chamber while the shaft changes are being made above. In Figs. 6, 7, and 8" one form of partition is shown. It comprises two half partitions 4O hinged together by hinges 42. Ad jacent. the hinges each half partition has a downwardly projecting flange 44, and between the flanges, when the partition is in operative position, is a sheet'of resilient packing 46 to prevent leakage of air. Around the outer edge of the upper side of the partition is a ring 48 of resilient packing. Within the upper end ofeach section of shaft 22 is a steel ring 50. To apply the partition, it is folded at the hinge, lowered below ring 50, and then raisedby chains 52 into its operative position (Fig. 7), and then air valve 54 and hose 56 are attached, through which air is supplied to the shaft and chamber below the partition. After the lock has been opened preparatory to its removal, the air pressure below the partitionserves to hold the partition in operative position without the assistancefof chains 52. While, removing the lock and attaching the new shaft section, hose 56 may be temporarily disconnected. Itis only necessary to have-the hoseconnected sufliciently to replace any air whichmay leak slowly past partition 40.
After the lock is replaced andthe pressure equalized, the partition may be removed.
The hole is thus excavated down to rock or other footing 58 after which the footing is prepared for concrete. After inspection, the men go out through the lock and the pouring of concrete begins. The concrete 59 is introduced through the concrete hopper 60 then rises.
(Fig. 6) and door 62 on the lower end of the hopper in the usual manner. When the concrete has reached a sutficient height, the caisson is made slightly buoyant by removing enough of the weights 26 or, if the frictional resistance has been sufficient to make the weights 26 unnecessary, by slightly increasing the air pressure to press downwardly againstthe concrete and upwardly against thecaisson. The slightly buoyant caisson This rising may be controlled either by addingorremoving enough of the weights 26 or by increasing or reducing the air pressure or by both. As the caisson is thus raised, more concrete is added until the caisson reaches a level where the'weight of concrete, above the bottom edge, of the working chamber, equals the external pressure there. When that level is reached, weights 26, platform 28, concrete hopper 60,
lock 24, and some of the shafting 22 are removed. Concrete hopper 6O is'then connected directly to the top flange of the remaining shafting 22 and, air being admitted through pipe 66 (Figs. 3 and 5), the concreting and raising process is resumed.
. As the working chamber and shaft rise, the water or mud-laden fluid 68 surrounding the shaft is displaced outof the top of the.
hole. The shaft is successivelyshortened untilthe concrete in the excavation reaches the required height, whereupon'the remainder of the shaft, and the working chamber are hoisted out of the hole, leaving the finished column as in Fig. 4.
The recovered work chamber and shaft may be re-used, as desired.
It is to be understood that the invention is not limited to the'specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.
1. A caisson for sinking a hole in the ground, comprising in combination, a working chamber of substantially the diameter of the hole, a shaft of lesser diameter extending from the top of said chamber and being free of the walls of the hole, and means for preventing entranceof extraneous material into said caisson. I
2. Apparatus for sinking a hole inthe ground, comprising in combination, a workin gchamber of substantially the diameter of the hole, a shaft of lesser diameter extending from the top of said chamber and being free of the walls of the hole, and an airlock on the top of said shaft, substantially as described.
3. Apparatus for sinking a hole in the ground, comprising in combination, a working chamber, a shaft extending upwardly from said chamber, said'shaft comprising comparatively short sections, each section having an internal circumferential band therein, and a collapsible partition insertable through the top of said shaft to a position below any one'of said bands and expansible thereunder and in contact therewith for providing a substantially airtight ance between the caisson and walls of the hole.
5. In the method of digging a hole in the ground with a caisson, the steps oflowering the caisson as the digging proceeds and gradually increasing the length thereof, maintaining substantially constant frictional re sistance between the caisson and walls of the hole and withdrawing the caisson after the hole is completed.
' 6. In the method of forming a concrete column in the ground with a caisson, the steps of lowering the caisson until a hole of the desired depth is provided, depositing plastic concrete in the interior of the caisson, and introducing fluid under pressure into said caisson above said concrete whereby said caisson is forced upwardly from said hole.
7 In the method of digging a hole in the ground, the steps of providing a caisson having a working chamber at its lower end and a shaft of less diameter than the chamber and free of the walls of the hole extending up wardly from said chamber and excavating the ground below said caisson until the chamber reaches the desired depth and filling the caisson with plastic concrete.
8. In the method of digging a hole in the ground, the steps of providing a caisson having a working chamber at its lower end and a shaft of less diameter than the chamber and free of the walls of the hole extending upwardly from said chamber, excavating the ground below said caisson until the chamber reaches the desired depth, introducing plastic concrete into the hole through said caisson, and withdrawing the caisson gradually as the introduction of concrete proceeds. v
9. In the method of digging a hole in the ground, the steps of providing a caisson having a working chamber at its lower end and a shaft of less diameter than the chamber and free of the walls of the hole extending upwardly from said chamber, excavating the ground below said caisson until the chamber reaches the desired depth, introducing plastic concrete into the hole through said caisson, introducing fluid under pressure into said caisson above the concrete whereby the caisson is forced upwardly from the hole.
10. In the method of digging a hole in the ground, the steps of providing a caisson having a working chamber at its lower end and a shaft of lessdiameter than the chamher and free of the walls of the hole extendlng upwardly from said chamber, excavating below the caisson whereby the caisson sinks into the ground, and applying an increasing load to the roof of the working chamber as the caisson sinks lower into the ground.
11. In the method of digging a hole in the ground, the steps of providing a caisson having a working chamber at its lower end and a shaft of less diameter than the chamber and free of the walls of the hole extending upwardly from said chamber, excavating below the caisson whereby the caisson sinks into the ground, and preventing collapse of the. wall of the hole above said chamber by maintaining liquid in the hole above said chamber.
12. The method of sinking a caisson in the ground to form a hole, which consists in excavating the ground below said caisson, maintaining fluid pressure tending to lift said caisson, and applying a fluid load to 7 said caisson within the hole tending to neutralize the pressure acting to lift the caisson.
13. The method of sinking a caisson in the ground to form a hole, which consists in excavating the ground below said caisson, maintaining fluid pressure within the caisson tending to lift said caisson, and maintaining a liquid load exterior of the caisson and within the hole tending to neutralize the'action of the fluid pressure and preventing collapse of the wall of the hole.
In testimony whereof I hereto afiix my signature.
CHARLES L. POWELL.